[LeArc] Forecast Discussion : MLI@ 8/8/2003 2:59:40 PM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 081956
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
255 PM CDT FRI AUG 8 2003

LITTLE CHANGE IN THE PATTERN THIS WEEK AS NORTHERLY FLOW DOMINATES
ALOFT WITH HIGH PRESSURE AT THE SURFACE.  LAKE ENHANCED CLOUDINESS
CONTINUES MOVING INTO THE CWA AND SOME WEAK SHOWERS ARE POPPING UP IN
THE EASTERN PART OF THE CWA.

TONIGHT AND SATURDAY...
NEAR PERSISTENCE SEEMS TO BE THE BEST FORECAST AND MODELS DO LITTLE
TO SUPPORT OTHERWISE.  MIN TEMPS TONIGHT NEAR GUIDANCE LOOK
REASONABLE...WITH HIGHS TOMORROW PERHAPS A FEW DEGREES WARMER TODAY
WITH A LITTLE LESS CLOUD COVER.  SHOWER CHANCES ARE SMALL AND
CONFINED MAINLY TO EAST OF THE MISSISSIPPI RIVER...BOTH THIS EVENING
AND TOMORROW AFTERNOON.  THERE IS MORE MID LEVEL DRY AIR TODAY THEN
YESTERDAY...THUS SHOWERS SHOULD REMAIN ON THE WEAK SIDE.  ...WOLF

.SATURDAY NIGHT THROUGH FRIDAY...
CHANGES TO OMEGA BLOCK PATTERN TO TAKE PLACE BY MIDDLE OF NEXT WEEK
AS UPPER RIDGE OVER WESTERN CONUS FLATTENS AND BECOMES POSITIVELY
TILTED OVER NORTHERN PLAINS AND PERSISTENT GREAT LAKES UPPER TROUGH
FINALLY BREAKS DOWN. UNTIL THEN...PARADE OF WEAK UPPER WAVES
ROTATING OVER TOP OF RIDGE CONTINUE TO AFFECT MAINLY AREAS TO WEST
OF FORECAST AREA. THE STRONGEST OF THESE FEATURES PUSHES THROUGH
SUNDAY NIGHT INTO MONDAY ACCOMPANIED BY WEAK SURFACE COLD FRONT. GFS
IS ODD MODEL OUT WITH STRONG H5 VORT MAX PUSHING THROUGH WESTERN IA
MONDAY MORNING...WHILE ECMWF AND UKMET HAVE WEAKER WAVE WITH
SIGNIFICANT TIMING DIFFERENCES. FOR NOW...OPTED TO TAKE MIDDLE OF
ROAD BLEND AND EXPAND SLIGHT CHANCE POPS TO MOST OF FORECAST AREA
FOR SUNDAY AFTERNOON AND EVENING...AND THEN OVER ENTIRE AREA SUNDAY
NIGHT. FORCING IS WEAK AND MAINLY OVER AREAS TO WEST...BUT WITH
DEVELOPING UPPER DIFLUENCE AHEAD OF WAVE AND MODERATELY UNSTABLE
AIRMASS INDICATED SUNDAY AFTERNOON ESPECIALLY OVER EAST...WENT AHEAD
AND EXPANDED TO BETTER COORDINATE WITH SURROUNDING OFFICES.

FEW CHANGES TO TEMPERATURE GRIDS. FOLLOWED PERSISTENCE WHICH IS
CLOSE TO GUIDANCE SUNDAY...THEN SLIGHT COOL DOWN MONDAY FOLLOWING
FROPA. UPPER HIGH MOVING OVERHEAD BY LATE WEEK AND LOW LEVEL FLOW
BECOMING SOUTH TO SOUTHWEST WILL RESULT IN WARM UP INTO MID TO UPPER
80S THU AND FRI WITH TYPICAL AUGUST DEWPOINTS HOLDING OVERNIGHT LOWS
IN MID 60S. ...SHEETS

DVN...
IA...NONE.
IL...NONE.
MO...NONE.

$$